The answer you're looking for might be "backwards-compatible".
Answer:
B
Explanation:
This feels like an error on the question issuer's part.
Answer:
Handheld/Mobile Computers
The correct answer to this question is letter "C. type of service provider."
Here are the following choices:
<span>A. subject matter of the message.
B. type of software being used.
C. type of service provider.
D. location of the destination</span>